File-by-File patching shrinks the size of Android app updates, resulting in data savings

The Android Developers Blog reported today that changes to the software are reducing the amount of data consumed when updating apps on an Android device. Earlier this year, Android switched to the bsdiff algorithm for updates, reducing the size of app updates by 47% when compared to apps updated in full APK size.

But Google's software engineers have improved upon this with a new system called File-by-File patching. Using this technique, the size of an app update could shrink 65% to as much as 90%. As a result, less data is consumed while updating. Of course, using a Wi-Fi network would save all of your data, but most users don't take the time to make sure that they have a Wi-Fi connection before updating a few apps from the Play Store.

According to Google, using File-by-File patching will save 6 petabytes of user data each day. Considering that each petabyte is equivalent to a million GB, we're talking about saving some serious amounts of data here. Take a look at the chart that accompanies this story, and you can get a feel for the amount of data you're saving. For example, with a recent update to Google Maps the file size was 32.7MB. Using the bsdiff algorithm reduced the size by 46% to 17.5MB. Using File-by-File patching resulted in a savings of 71% from the original file to 9.6MB.

File-by-File patching is open source, so if you're interested in making contributions to reducing file sizes by a larger amount, click on this link.


source: AndroidDevelopersBlog